Chen, Bing Zhen http://orcid.org/0000-0003-4577-9671
Zhai, Wen Juan
Funding for this research was provided by:
the Project for Youth Scholars of Higher Education of Hebei Province (QN2017402)
the Project of Teaching Research and Practice of Higher Education of Hebei Province (2017GjjG364)
the Project of Teaching and Research of Beijing Jiaotong University Haibin College (HBJY16005)
Article History
Received: 2 April 2018
Accepted: 14 November 2018
First Online: 20 November 2018
Competing interests
: The authors declare that they have no competing interests.